Men will still need a prescription to buy the pills at viagra.com and they are pricier than the fakes at $25 a pop – though Pfizer is offering three free tablets with a first order and a 30pc discount with a second.

Launched in 1998, Viagra took the world by storm. Ad campaigns were fronted by the likes of Pele, whose insistence he didn’t actually need the pills himself led to headlines professing the footballer could “still do keepy-uppy”.

But, while Pfizer has the patent until 2020, fakes have hit sales - down 7pc in the first three months of 2013 to $461m. Other drug companies will now be keeping a keen eye on Viagra sales.

Traditionally drug-makers sell to wholesalers, which distribute drugs to doctors, hospitals and pharmacies.

Pfizer may have hit upon a new route to market for other embarrassing afflictions. Hair loss pills anyone?